Fluorescence studies on anthryl bacteriorhodopsins

Abstract

Fluorescence properties of bacteriorhodopsin analogues containing 3-methyl-5-(9'-anthryl)-2E,4E-pentadienal and 3,7-dimethyl-9-(9'-anthryl)-2E,4E,6E,8E-nonatetraenal chromophores as built-in fluorescence probes are described. Determination of fluorescence quantum yields, fluorescence quenching and energy transfer efficiencies in terms of the Förster's energy transfer between tryptophans (Trp) and the anthrylidene moiety indicates that Trp residues lie at a critical distance (R₀) of ca. 27 Å from the chromophore bound at Lys-216 on the apo-protein.